It this solution is so obvious, I don't understand why autotools
developers have not already set up a tool which automatically
removes the files generated by the autotools (perhaps this tool
exists and I don't know about).

It is called 'make maintainer-clean'. Unfortunately, if time stamps
are wrong, the Makefile may try to rebuild itself before executing
the target.

I tried this command, but it does not clean up all configure, stamp*,
aclocal.m4, ... that was generated by the autotools.
I guess that these must be removed by hand (or better ignored in the
versioning system, if it is possible to get an